Electric control device



June 26 1934 c. lT. EVANS 1,964,199

ELECTRLQ csNTfvr. DEVICE Filed Dec/19,

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ELECTRIC CQNTBOL DEVICE Clarence T. Evans. Wauwatosa, Wis., assigner toCutler-Hammer, Inc., Milwaukee, Wis., a cor- Dotation oi DelawareApplication December 19, 1932, Serial No. 647,951 8 Claims. (Cl. 209-4)Thisinvention relatestoelectric control devices, tacts 1 and 2 isprovided with an inverted L- and while not limited thereto isparticularly apshaped bracket 15 iixed to the front face of inplicableto frictionally operated switches for use sulating base 12 by a terminaldevice 16 including in alternating current motor control systems to asecuring screw located within an opening in effect control of pluggingconnections. said insulating base, as shown in Fig. 4. The 00 Theinvention has among its objects to provide brackets 15 have contact tips17-l7 fixed to the an improved frictionally operated switch for useupper ends thereof, and the movable contact elein systems of theaforesaid character which is of ment 3 is provided with a support 18having consimple, rugged and compact construction. tact tips 19-19mounted upon the lower face 1:) Another object is to provide a switch ofthe thereof to cooperate with the former contact tips. 65-

aforesaid character having novel and eillcient Thel upper face ofcontact support 1B is provided friction operating means associatedtherewith, with spaced lugs 20-20 having openings therein Various otherobjects and advantages of the for receiving pivot pin 4, and as shown inFig. 3 invention will hereinafter appear. Ybelt 6 is secured to oppositeends of said contact 15 The accompanying drawing illustrates anemsupport by screws 2i having clamping plates 22 70 bodiment of theinventionwhich will now be deassociated therewith. scribed, it beingunderstood that the embodiment The spring pressure device 8 includes avertiillustrated is susceptible oi' modification without cally arrangedpin 23 carried by a bracket 24 departing trom the spirit and scope ofthe fixed toinsulating base 12 by screws 25. Pin 23 is 2Q appendedclaims. slidably` mounted within openings in spaced for- 75 In thedrawing, wardly extending lugs 26 and 27 on bracket24, Figure l is afront elevational view of an enand the upper end of said pin is locatedwithin closed frictionally operated switch embodying the an opening inpivot pin 4 and is provided with invention, the. cover of the enclosingcasing being an enlarged head 29 for engaging said pivot pin removed. Yon the upper side thereof. Pin 23 is biased to 80 Figs. 2 and 4 arevertical sectional views taken move downwardly by a coiled spring 30which suron lines 2-2 and 4 4. respectively, of Fig. 1. rounds said pinand is held under compression Fig. 3 is an enlarged fragmentaryview,'partly between a washer 31 which abuts the upper lug 26 insection, of certain of the .switch parts shown in on bracket 24. and awasher 32 which abuts'a ,o Fig, 1 cotter pin 33 located within anopening in pin 23. 85

Pig. 6 ditically illustrates the switch As shown in Fig. 3y the contactsupport 18 is slotas applied to a plllsins control system i'or inductedat 34 to clear the pin 23, and for a purpose tion motors. hereinafterset forth the under side of said sup- The control switch illustrated inthe drawing port is provided with a fiat face 35 for coopera- -35includes spaced stationary contacts l and 2, and tion with the top faceof the upper lug 26 on 90 a cooperating movable contact element 3pivotbracket 24. ally mounted at a point intermediate said sta- Ashereinbefore stated, the drive shaft 'l is rotionary contacts' upon apin 4. 'I'he operating tatably mounted within a bearing 14'provided inmechanism for contact element 3 comprises a the upper end ofcasing 9. Asshown in Fig. 2 the o pulley 5 and a belt 6 looped over said pulley andbearing 14 includes spaced ball bearings 36- and 95 connected toopposite ends of said contact ele- 37 having their inner races mountedupon shaft 'I v ment, said pulley being fixed to a drive shaft '1, andhaving their outer races supported within a and said belt beingheldunder tension by a spring hollow cylindrical projection 38 extendingfor-'1 pressure device 8 associated with pivot pin 4. wardly fromthejrear wall of casing 9. Shaft 7 The aforementioned switch parts aremounted and its associated ball bearings are held in aswithin a boxshaped enclosingcasing 9 provided sembied relation within projection 38by a rewith a removable cover 10 which is secured to said taining ring39 tlxed to the rear wall of casing 9 casing by screws 1l,` shown insection in Pig. i. by screws40. and said shaft has a portion pro- Aninsulatinbase 12 xedto the rear wall of Jecting rearwardly beyond saidretaining ring casing 9 by screws 13 carries stationary contacts forconnection to a driving part such as the shaft 105 1 and2.m0vble WDMelmnt 3.*Ddthe Spring of a reversible electric motor. An opening 41pressure device 8, and the drive shaft 'l is rotathaving a removablescrew plug 42 associated ably mounted-within a bearing 14 provided inthe therewith is provided for introducing a lubricant upperendofsaidcasing. l to thel ball bearings 36 and 37, and to Vprevent Morespeciiically, each of the stationary con-y leakage of the lubricant aprojecting hub portion 110 i3 on pulley 5 ts within a grooved opening inthe front end of the hollow cylindrical projection 3S and shaft '7 litswithin a grooved opening in retaining ring 39.

The function and operation of the aforedescribed device will now be morefully described. As is apparent, the spring pressure device 8 tends to.move the contact support 18 into the position shot/'n in dotted linesFig. 3. However, the belt is of such length es to hold Contact supporti8 in an elevated position, and the belt is thereby placed under tensionby the spring pressure de vice il. Thus the belt provides a slip drivingconnection between pulley 5 and the movable contact element 3. As isapparent from Figs. l and 3,

upon rotation of pulley 5 in a clockwise direction 'the movable contactelement 3 is maintained in engagement with stationary contact 2 and outof engagement with stationary contact l, and upon rotation of saidpulley in a counterclockwise direction said movable contact ismaintained in engagement with stationary contact l, and out ofengagement with stationary contact 2. Also as is apparent from Figs. land 3, upon a change in the direction of operationof pulley 5 themovable contact element 3 is immediately tilted upon its pivot pin Il tochange the position thereof. In connection with the foregoing it shouldbe noted that if +he belt 6 breaks or slips oil of the pulley 5 springpressure device 8. moves the contact elenient 3 into the position shownin dotted lines in B, and in this position the face on contact supporti8 engages the top lface of the lug 26 on bracket 2e to maintain saidcontact element out oi engagement with its cooperating stationarycontacts l and 2.

The above described device may beused in a system suoli as shown in Fig.5 to control plugging of a three phase induction motor M. In the systeinshown in this iigure the supply circuit for the motor is indicated bylines Ll-L2-L3, and electroresponsive switches F and R are provided forselectively establishing forward and reverse power connections for themotor. The energizing circuit for the operating winding of switch F iscontrolled by a manually operated switch and the above describedirictionally operated switch is connected to the shaft of motor M and isarranged to control the energizing circuit of switch F through themedium of normally closed auxiliai'y contacts 46 associated with switchF. As is apparent from Fig. 5, closure of switch 45 effects response ofswitch F by connecting the operating winding of said switch across linesL1L2. Switch F establishes power connections for motor M to causerotation thereof in a direction to maintain the contact element 3 inengagement with its cooperating stationary contact 2. Opening of switch45 deenergizes switch F and immediately upon dropping out of saidswitch, switch Pt is energized by a circuit extending from line L1through the operating winding of said letter switch, through stationarycontact 2 and movable contact 3 ci the frictionally operated switch andauxiliary contacts 46 of switch F to line L2. Switch R in respondingestablishes reverse power connections for the motor to effect pluggingthereof. At the instant the motor reverses under the action of saidreverse power connections contact element 3 moves out of engagement withstationary contact 2 to interrupt the energizing circuit for switch R,whereupon the motor is brought to rest.

As shown in Fig. l, the lower screw 25 associated/with bracket 24 isconnected to the movable contact element 3 by a flexible lead 47 andserves as a Wiring terminal for said contact clement. Also as shown inFig. l one of the side walls of casing 9 has a wiring opening 48therein, and the rear wall of said casing has openings 49 thereinthrough which bolts may be passed for securement of the device to asuitable support.

What I claim as new and desire to secure by Letters Patent is:

l. In a frictionally operated switch, the combination with a contactelement movable in op posite directions between given circuitcontrollingpositions, of a driving pulley therefor, a belt looped over said drivingpulley and connected to said contact element to provide a slip operatingconnection for frictionally holding said element in one position uponrotation of said pulley in one direction, and to move the saine into itsop` posite position upon initial rotation of said pulley in a reversedirection and spring means to effect tensioning of said belt.

2. In a frictionally operated switch, the combination with a Contactelement movable in opposite directions between given circuit-controllingpositions, of a driving pulley therefor, a frictional operatingconnection between said pulley and said element to frictionally holdsaid element in one of said positions upon rotation of said pui ley inone direction and to move the same into its opposite position uponinitial rotation of said pulley in a reverse direction, and means forbies ing said element to insure positioning thereof in an intermediateposition but only upon failure of said frictional operating connection.

3. In a frictionally operated switch, the combination with a contactelement movable in opposite directions between given circuit controllingpositions, of a driving pulley therefor, c. belt looped over said pulleyand connected to said Y Contact element to provide a slip operatingconnection for frictionally holding said element in one position uponrotation of said pulley in one direction, and to move the same into itsopposite extreme position upon initial rotation o! said pulley in areverse direction, and spring means associated with said element forbiasing the same to effect tensioning of said belt.

4i. In a frictionally operated switch, the combination with a pivotedContact element movable in opposite directions between givencircuit-controlling positions, o! a driving pulley therefor, a beltlooped over said pulley and operatively connected to said contactelement on opposite sides of the pivot thereof, and a. spring pressuredevice for biasing the pivot o1' said contact element in a direction toeffect tensioning of said belt.

5. In a frictionally operated switch, the combination with a pair ofstationary contacts and a cooperating movable contact element having anassociated pivot pin arranged intermediate said stationary contacts, ofa reversible driving pulley, a belt looped over said pulley andconnected to said contact element on opposite sides of said pivot pin toprovide a slip operating connection for moving said Contact element intoand out o! engagement with one or the other of said stationary contactsin accordance with the direction of rotation of said pulley, a springassociated with said pivot pin to bias said contact element in a fdirection to effect tensioning of said belt, and a xed stop, saidContact element being movable into engagement with said stop under theaci-ion of said spring upon failure o! said belt, to insure movement ofsaid contact into out nection for moving said contact element intoandout of engagement with said stationary contact upon rotation of saidpulley in opposite -direc.

tions, a spring associated with said pivot pin to bias said contactelement in a direction to en'ect tensioning of said belt, and a fixedstop for limiting movement of said contact element under the action ofsaid spring upon failure of said belt, said stop and said contactelement having cooperating surfaces which insure'movement of saidcontact element out of engagement with said stationary contact uponfailure of said belt. A

7. In a frictionally operated switch, in combination, an enclosingcasing, an .insulating base mounted within said casing, a switch mechafnism mounted upon said base, including a sta.-

tionary contact and a cooperating movable contact element having a pivotpin associated therewith, a pulley within said casing having anassociated drive shaft Journaled in one of the walls of said casing, abelt looped over said pulleyand connected to said contact element onopposite sides of its associated pivot pin toprovidev for of engagementwith said stationary contact upon rotation of said pulley in oppositedirections, and a spring pressed pin slidably mounted upon saidinsulating base and connected to the pivot pin associated with saidcontact element to bias the latter in a direction to effect tensioningof said belt.

8. In a frictionally operated switch, in combination, an enclosingcasing, an insulating base mounted upon the rear wall of said casing, a

switch mechanism mounted upon said base including a stationary contactand a cooperating movable contact element having a pivot pin associatedtherewith, a. pulley within said casing having an associated drive shaftjournaled in the rear wail of said casing, a belt looped over said"pulley and connected to said contact element on opposite sides of itsassociated pivot pin to provide for movement of said'contact elementinto and out of engagement with said stationaryv contact upon rotationof said pulley in opposite directions; a bracket mounted 'upon saidinsulating base, a spring premed pin slidably mounted upon said bracketand connected to the pivot pin associated with said contact element tobias the latterin a direction to eifect tensioning of said belt.' saidcontact element and said bracket having cooperating surfaces adapted toengage upon failure of said belt toinsure disengagement of said acontact element with said stationary contact. v y y CLARENCE T.

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